JPH03235442A - Ciphered communication system - Google Patents

Abstract

PURPOSE:To transmit key information whenever it is necessary without interrupting information communication by sending the key information and ciphered information to be transmitted independently through different channels, and receiving these independently by a receiving side. CONSTITUTION:The key information for ciphering and deciphering generated by a key information generation circuit 7 is sent to a key storage circuit 6 and a key transmission circuit 31 respectively, and is stored in these. Besides, the key information sent to the key transmission circuit 31 is sent to a key reception circuit 21 through a key transmission channel 4, and the key reception circuit 21 stores this received key information in the key storage circuit 10. On the other hand, the information I desired to send is sent to a ciphering circuit 5, and is ciphered by the key information stored before in the key storage circuit 6, and is sent to a deciphering circuit 11a through an information communication channel 3. The deciphering circuit 11a deciphers it by the key information stored before in the key information storage circuit 10, and restores it to the original information I.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention secures confidentiality of information without interrupting communication when performing broadcast-style communication used in satellite communication, etc. This invention relates to an encrypted communication system that enables

(Prior Art) When performing broadcast-style communications used in satellite communications, etc., encryption is performed to ensure the confidentiality of the communicated information.

In this type of conventional system, the central station transmits the encrypted communication information to the local station while delivering key information for decoding the encrypted information. That is, since the key distribution channel and the information channel use the same channel, the encrypted information body is transmitted after the key information is distributed.

Therefore, in this conventional method, when keys must be distributed to ensure confidentiality, or when the number of local stations increases or decreases, or when key information is changed, the key information and the communication information itself cannot be sent at the same time, so the communication information itself cannot be transmitted. There was a problem in which interruptions were unavoidable.

The conventional method will be specifically explained below with reference to FIG.

As shown in the figure, the conventional system consists of an encryption device 1 installed at a center station on the transmitting side that encrypts and transmits information I to be transmitted, and a local station that decrypts this encrypted received information and reproduces information I. It consists of a network mainly consisting of an installed decoding device 2, a broadcast communication channel 3 that connects both stations,
The cryptographic device 1 includes a key generation circuit 7 that generates key information used for encryption, a line memory circuit 6 that stores the key information generated by the key generation circuit 7, and a line memory circuit 6 that stores key information that is stored in the line memory circuit 6. an encryption circuit 5 that encrypts and transmits the information I to be transmitted using the key information obtained; selectively extracts either one of the key information from the information processing unit to be transmitted or the key generation circuit 7 and sends it to the encryption circuit 5; Each device is constituted by a switching circuit 8 for providing the signal, a line storage circuit 10 in the decoding device 2, and a decoding circuit 11.

The line storage circuit 10 has a decoding circuit 11 connected to the broadcast communication channel 3.
The decryption circuit 11 is a circuit for storing key information received via the broadcast communication channel 3, and the decryption circuit 11 receives information sent from the encryption device 1 via the broadcasting communication channel 3. Among the received information, the key information is stored in the line storage circuit 10. The encrypted information (2) is decrypted using the key information stored in the line storage circuit 1o, and the information (2) is restored and output.

In the above configuration, the main operation is to encrypt information 1 with the center station encryption device, decrypt it with the local station decryption device 2 via the information communication channel 3, and obtain the original information 1.

In order to perform such an operation, first, key information for encryption and decoding is generated in the key generation circuit 7, the key information is sent to the line storage circuit 6 to be stored, and the switching circuit 8 into key distribution mode. As a result, the key information generated by the key generation circuit 7 is also sent to the encryption circuit 5 via the switching circuit 8, and the encryption circuit 5 sends it to the receiving side via the broadcast communication channel 3. Then, on the receiving side, the key information is received by the decryption circuit 11, and the decryption circuit 11 sends the received key information to the line storage circuit 10 to be stored therein.

When the key distribution is completed, the information 1 is then sent to the encryption circuit 5 via the switching circuit 8. Then, the encryption circuit 5 encrypts the information 1 using the key information stored in the line storage circuit 6 and transmits it. This encrypted information I is decrypted by the receiving side decryption circuit 11 using the key information stored in the line storage circuit 10, and is restored to the original information 1.

Thereafter, the encryption of information 1 continues, but if the key information is to be changed midway through, it must be done by temporarily interrupting the transmission of information 1 and setting the switching circuit 8 to key distribution mode. .

(Problems to be Solved by the Invention) As described above, when performing broadcast-style communication used in satellite communication, etc., encryption is performed to ensure the confidentiality of the communicated information. Then, the sending side generates key information for encryption and decryption, sends this to the receiving side, encrypts the information to be communicated using this key information and sends it, and the receiving side uses this encrypted information. The received information is decrypted using the received key information.

In the conventional method, the information communication channel and the key distribution channel are shared, so if you try to distribute the key information during information transmission, the information communication will be interrupted, and smooth communication cannot be guaranteed. .

If key information is not changed to avoid interruptions in information communication, if the number of receiving stations increases or decreases, especially when the number of receiving stations increases, if key information cannot be transmitted, the increased number of stations will This is a problem because it means that it cannot be received. moreover,
If key information cannot be changed as desired, there will be problems in maintaining confidentiality.

Therefore, it is an object of the present invention to provide an encrypted communication system that allows key information for encryption to be delivered at any time without interrupting information communication.

[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, the present invention is configured as follows. That is, key information for encryption is generated on the sending side and sent to the receiving side, and the sending side uses the generated key information to encrypt the information to be sent, sends it, and receives it. In the communication system, the encrypted received information is decrypted using the received key information and the information is reproduced. a key transmitting means for transmitting using a key information distribution channel different from an information communication channel; and a key information provided on a receiving side to receive the key information transmitted via the key information distribution channel. and a receiving means for receiving the information.

(Function) When the system of the present invention wants to transmit key information, the generated key information uses an independent key information distribution channel different from the information communication channel for communicating the encrypted transmission information, Deliver to recipient. On the receiving side, this is received by the receiving means for the key information distribution channel, and is stored in the key information storing means. Decryption is performed on encrypted received information received via an information communication channel using the received and stored key information.

In this way, the key information is distributed using an independent key information distribution channel separate from the information communication channel, and the receiving side receives the key information using an independent receiving means for the key information distribution channel and decrypts it. Since it is used, key information can be transmitted at any time without interrupting the transmission of encrypted transmission information. Since key information can be sent without hindrance to communication, smooth communication is guaranteed and security can be further ensured. Even with an increase in the number of receiving stations, key information can be sent at any time. Since the information can be given, the receiving side can receive and restore information at any time.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, in which 30 is an encryption device, 20 is a decryption device, 3 is an information communication channel, 4 is a key distribution channel, 5 is an encryption circuit, and 6 is a key storage circuit. , 7 is a key generation circuit, 31 is a key transmission circuit, 10 is a key storage circuit, lla is a decryption circuit, and 21 is a key reception circuit.

The encryption device 30 is for encrypting and transmitting the information I to be transmitted, and here, in addition to the broadcast communication channel 3, a key distribution channel 4 can be used. The decryption device 20 is for decoding the encrypted received information obtained from the transmitting side via the broadcasting communication channel 3 and reproducing the information processing, and the key information is not from the broadcasting communication channel 3 but from the key. It is configured to receive using delivery channel 4.

The encryption device 20 includes a key generation circuit 7 that generates key information used for encryption, a key storage circuit 6 that stores the key information generated by the key generation circuit 7, and a key stored in the key storage circuit 6. It has an encryption circuit 5 that encrypts the information I to be transmitted using the information and transmits it, and a key transmission circuit 31 that transmits the key information from the key generation circuit 7 using the key distribution channel 4. , the decryption device 20 includes a key receiving circuit 21 that receives key information from the key transmitting circuit 31 transmitted through the key distribution channel 4, a key storage circuit 10 that stores the key information received by the key receiving circuit 21, and a broadcasting device. The transmitted information from the cryptographic device 1 is received via the system communication channel 3, and the encrypted information I, which is the received information, is decrypted using the key information stored in the key storage circuit 10, and the information I is It has a decoding circuit 11a that restores and decodes 8 images.

In this apparatus having such a configuration, the key information for encryption and decryption generated by the key generation circuit 7 is sent to the key storage circuit 6 and the key transmission circuit 3 respectively. The key information sent to the key storage circuit 6 is stored here. Further, the key information sent to the key transmitting circuit 31 is sent to the key receiving circuit 21 via the key distribution channel 4, and the key receiving circuit 21 stores the received key information in the key storage circuit 10.

On the other hand, the information to be communicated is sent to the encryption circuit 5, encrypted using the key information already stored in the key storage circuit 6, and sent via the information communication channel 3 to the decryption circuit 11a. The decryption circuit 11a decrypts the data using the key information already stored in the key storage circuit 10, and restores the original information (2).

In this way, the key information and the encrypted information to be sent are sent independently through separate channels, and the receiving side receives them independently, so the necessary information can be sent at any time without interrupting information communication. Sometimes it becomes possible to distribute key information. Since key information can be sent without hindrance to communication, smooth communication is guaranteed and security can be further ensured. Even with an increase in the number of receiving stations, key information can be sent at any time. Since the information can be given, the receiving side can receive and restore information at any time.

[Effects of the Invention] As detailed above, according to the present invention, the key information and the encrypted information to be transmitted are sent independently through different channels, and the receiving side receives them independently. From, when without interruption of information communication? However, it is possible to provide an encrypted communication system that allows key information to be distributed when necessary.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. 3... Information communication channel, 4... Key distribution channel,
5... Encryption circuit, 6... Key storage circuit, 7... Key generation circuit, 10... Key storage circuit, 11a... Decryption circuit, 20... Decryption device, 21... Key Receiving circuit, 30・
... Encryption device, 31... Key transmission circuit.

Claims (1)

[Scope of Claims] Key information for encryption is generated on a transmitting side and transmitted to a receiving side, and the transmitting side encrypts information to be transmitted using the generated key information, In a communication system, the encrypted received information is decrypted on the receiving side using the received key information, and the information is reproduced. a key transmitting means for transmitting the encrypted transmitted information using a key information distribution channel different from a communication channel; 1. An encrypted communication system comprising: receiving means for receiving key information.